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<H1 class="no-header">curs_getch 3x 2025-02-15 ncurses 6.5 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>                   Library calls                  <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>




</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
       <STRONG>getch</STRONG>, <STRONG>wgetch</STRONG>, <STRONG>mvgetch</STRONG>, <STRONG>mvwgetch</STRONG>, <STRONG>ungetch</STRONG>, <STRONG>has_key</STRONG> - get (or push back)
       characters from <EM>curses</EM> terminal keyboard buffer


</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
       <STRONG>#include</STRONG> <STRONG>&lt;curses.h&gt;</STRONG>

       <STRONG>int</STRONG> <STRONG>getch(void);</STRONG>
       <STRONG>int</STRONG> <STRONG>wgetch(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>mvgetch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG>
       <STRONG>int</STRONG> <STRONG>mvwgetch(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG>

       <STRONG>int</STRONG> <STRONG>ungetch(int</STRONG> <EM>c</EM><STRONG>);</STRONG>

       <EM>/*</EM> <EM>extension</EM> <EM>*/</EM>
       <STRONG>int</STRONG> <STRONG>has_key(int</STRONG> <EM>c</EM><STRONG>);</STRONG>


</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>

</PRE><H3><a name="h3-Reading-Characters">Reading Characters</a></H3><PRE>
       <STRONG>wgetch</STRONG> gathers a key event from the terminal keyboard associated with a
       <EM>curses</EM>   window  <EM>win</EM>.   <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>  describes  the  variants  of  this
       function.

       When input is pending, <STRONG>wgetch</STRONG> returns an integer  identifying  the  key
       event; for alphanumeric and punctuation keys, this value corresponds to
       the character encoding used by the terminal.  Use of the control key as
       a  modifier,  by  holding  it down while pressing and releasing another
       key, often results in a distinct code.   The  behavior  of  other  keys
       depends  on whether <EM>win</EM> is in keypad mode; see subsection "Keypad Mode"
       below.

       If no input is pending, then if the no-delay flag is set in the  window
       (see  <STRONG><A HREF="nodelay.3x.html">nodelay(3x)</A></STRONG>),  the  function returns <STRONG>ERR</STRONG>; otherwise, <EM>curses</EM> waits
       until the terminal has  input.   If  <STRONG><A HREF="curs_inopts.3x.html">cbreak(3x)</A></STRONG>  or  <STRONG><A HREF="curs_inopts.3x.html">raw(3x)</A></STRONG>  has  been
       called,  this  happens after one character is read.  If <STRONG><A HREF="curs_inopts.3x.html">nocbreak(3x)</A></STRONG> or
       <STRONG><A HREF="curs_inopts.3x.html">noraw(3x)</A></STRONG> has been called, it occurs when the  next  newline  is  read.
       (Because  the  terminal's  canonical or "cooked" mode is line-buffered,
       multiple <STRONG>wgetch</STRONG> calls may then be necessary to empty the input  queue.)
       If <STRONG><A HREF="curs_inopts.3x.html">halfdelay(3x)</A></STRONG> has been called, <EM>curses</EM> waits until input is available
       or the specified delay elapses.

       If <STRONG><A HREF="curs_inopts.3x.html">echo(3x)</A></STRONG> has been called, and the window is not a pad, <EM>curses</EM> writes
       the returned character <EM>c</EM> to the window (at the cursor position) per the
       following rules.

       <STRONG>o</STRONG>   If <EM>c</EM> matches the terminal's erase  character  (see  <STRONG><A HREF="curs_termattrs.3x.html">erasechar(3x)</A></STRONG>),
           the  cursor  moves  leftward  one  position and the new position is
           erased as if <STRONG><A HREF="curs_move.3x.html">wmove(3x)</A></STRONG> and then <STRONG><A HREF="curs_delch.3x.html">wdelch(3x)</A></STRONG> were called.   When  the
           window's   keypad   mode  is  enabled  (see  below),  <STRONG>KEY_LEFT</STRONG>  and
           <STRONG>KEY_BACKSPACE</STRONG> are handled the same way.

       <STRONG>o</STRONG>   <EM>curses</EM> writes any other <EM>c</EM> to the window, as with <STRONG><A HREF="curs_addch.3x.html">wechochar(3x)</A></STRONG>.

       <STRONG>o</STRONG>   If the window <EM>win</EM> has been moved or modified since the last call to
           <STRONG><A HREF="curs_refresh.3x.html">wrefresh(3x)</A></STRONG>, <EM>curses</EM> calls <STRONG>wrefresh</STRONG> on it.

       If  <EM>c</EM>  is  a carriage return and <STRONG><A HREF="curs_inopts.3x.html">nl(3x)</A></STRONG> has been called, <STRONG>wgetch</STRONG> returns
       the character code for line feed instead.


</PRE><H3><a name="h3-Keypad-Mode">Keypad Mode</a></H3><PRE>
       To <EM>curses</EM>, key strokes not from the alphabetic section of the  keyboard
       (those    corresponding    to    the    ECMA-6    character    set--see
       <STRONG>ascii(7)</STRONG>--optionally modified by either the control or shift keys)  are
       treated as <EM>function</EM> keys.  (In <EM>curses</EM>, the term "function key" includes
       but is not limited to keycaps engraved with "F1", "PF1",  and  so  on.)
       If  the  window  is  in  keypad  mode,  these  produce  a  numeric code
       corresponding to the <STRONG>KEY_</STRONG> symbols listed in subsection "Predefined  Key
       Codes"  below;  otherwise,  they transmit a sequence of codes typically
       starting with the escape character, and which must  be  collected  with
       multiple <STRONG>wgetch</STRONG> calls.

       <STRONG>o</STRONG>   The  <EM>curses.h</EM>  header  file  declares many <EM>predefined</EM> <EM>function</EM> <EM>keys</EM>
           whose names begin with <STRONG>KEY_</STRONG>; these object-like macros  have  values
           outside the range of eight-bit character codes.

       <STRONG>o</STRONG>   In   <EM>ncurses</EM>,   <EM>user-defined</EM>  <EM>function</EM>  <EM>keys</EM>  are  configured  with
           <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG>; they have no names, but are also expected  to  have
           values outside the range of eight-bit codes.

       A  variable  intended  to hold a function key code must thus be of type
       <EM>short</EM> or larger.

       Most terminals one encounters follow the ECMA-48  standard  insofar  as
       their  function  keys  produce  character  sequences  prefixed with the
       escape character ESC.  This fact implies that <EM>curses</EM> cannot distinguish
       a  user's  press  of  the  escape  key (assuming it sends ESC) from the
       beginning of a function key's character sequence without waiting to see
       if,  and  how  soon,  further input arrives.  When <EM>curses</EM> reads such an
       ambiguous character, it sets a timer.  If the remainder of the sequence
       does  not  arrive within the designated time, <STRONG>wgetch</STRONG> returns the prefix
       character; otherwise, it returns the function key code corresponding to
       the unique sequence defined by the terminal.  Consequently, a user of a
       <EM>curses</EM> application may experience a  delay  after  the  escape  key  is
       pressed  while <EM>curses</EM> disambiguates the input; see section "EXTENSIONS"
       below.  If the window is in "no time-out"  mode,  the  timer  does  not
       expire;  it  is  an infinite (or very large) value.  See <STRONG><A HREF="notimeout.3x.html">notimeout(3x)</A></STRONG>.
       Because function key sequences usually begin with ESC, the terminal may
       appear  to  hang  in no time-out mode after the user presses the escape
       key.  Generally, further typing "awakens" <EM>curses</EM>.


</PRE><H3><a name="h3-Ungetting-Characters">Ungetting Characters</a></H3><PRE>
       <STRONG>ungetch</STRONG> places <EM>c</EM> into the input queue to be returned by the  next  call
       to <STRONG>wgetch</STRONG>.  A single input queue serves all windows associated with the
       screen.


</PRE><H3><a name="h3-Predefined-Key-Codes">Predefined Key Codes</a></H3><PRE>
       The header file <EM>curses.h</EM> defines the following function key codes.

       <STRONG>o</STRONG>   Except for the special case of <STRONG>KEY_RESIZE</STRONG>, a window's  keypad  mode
           must be enabled for <STRONG>wgetch</STRONG> to read these codes from it.

       <STRONG>o</STRONG>   Not  all  of  these  are  necessarily  supported  on any particular
           terminal.

       <STRONG>o</STRONG>   The  naming  convention  may  seem  obscure,  with  some   apparent
           misspellings  (such  as "RSUME" for "resume"); the names correspond
           to  the  <EM>terminfo</EM>  capability  names  for  the   keys,   and   were
           standardized  before  the  IBM  PC/AT  keyboard  layout  achieved a
           dominant position in industry.

              <STRONG>Symbol</STRONG>          <STRONG>Key</STRONG> <STRONG>name</STRONG>
              -----------------------------------------------------------------
              <STRONG>KEY_BREAK</STRONG>       Break key
              <STRONG>KEY_DOWN</STRONG>
              <STRONG>KEY_UP</STRONG>          Arrow keys
              <STRONG>KEY_LEFT</STRONG>
              <STRONG>KEY_RIGHT</STRONG>

              <STRONG>KEY_HOME</STRONG>        Home key (upward+left arrow)
              <STRONG>KEY_BACKSPACE</STRONG>   Backspace
              <STRONG>KEY_F0</STRONG>          Function keys; space for 64 keys is reserved
              <STRONG>KEY_F(</STRONG><EM>n</EM><STRONG>)</STRONG>        Function key <EM>n</EM> where 0 &lt;= <EM>n</EM> &lt;= 63
              <STRONG>KEY_DL</STRONG>          Delete line
              <STRONG>KEY_IL</STRONG>          Insert line
              <STRONG>KEY_DC</STRONG>          Delete character
              <STRONG>KEY_IC</STRONG>          Insert character/Enter insert mode
              <STRONG>KEY_EIC</STRONG>         Exit insert character mode
              <STRONG>KEY_CLEAR</STRONG>       Clear screen
              <STRONG>KEY_EOS</STRONG>         Clear to end of screen
              <STRONG>KEY_EOL</STRONG>         Clear to end of line
              <STRONG>KEY_SF</STRONG>          Scroll one line forward
              <STRONG>KEY_SR</STRONG>          Scroll one line backward (reverse)
              <STRONG>KEY_NPAGE</STRONG>       Next page/Page up
              <STRONG>KEY_PPAGE</STRONG>       Previous page/Page down
              <STRONG>KEY_STAB</STRONG>        Set tab
              <STRONG>KEY_CTAB</STRONG>        Clear tab
              <STRONG>KEY_CATAB</STRONG>       Clear all tabs
              <STRONG>KEY_ENTER</STRONG>       Enter/Send
              <STRONG>KEY_SRESET</STRONG>      Soft (partial) reset
              <STRONG>KEY_RESET</STRONG>       (Hard) reset
              <STRONG>KEY_PRINT</STRONG>       Print/Copy
              <STRONG>KEY_LL</STRONG>          Home down/Bottom (lower left)
              <STRONG>KEY_A1</STRONG>          Upper left of keypad
              <STRONG>KEY_A3</STRONG>          Upper right of keypad
              <STRONG>KEY_B2</STRONG>          Center of keypad
              <STRONG>KEY_C1</STRONG>          Lower left of keypad
              <STRONG>KEY_C3</STRONG>          Lower right of keypad
              <STRONG>KEY_BTAB</STRONG>        Back tab key
              <STRONG>KEY_BEG</STRONG>         Beg(inning) key
              <STRONG>KEY_CANCEL</STRONG>      Cancel key
              <STRONG>KEY_CLOSE</STRONG>       Close key
              <STRONG>KEY_COMMAND</STRONG>     Cmd (command) key
              <STRONG>KEY_COPY</STRONG>        Copy key
              <STRONG>KEY_CREATE</STRONG>      Create key
              <STRONG>KEY_END</STRONG>         End key
              <STRONG>KEY_EXIT</STRONG>        Exit key
              <STRONG>KEY_FIND</STRONG>        Find key
              <STRONG>KEY_HELP</STRONG>        Help key
              <STRONG>KEY_MARK</STRONG>        Mark key
              <STRONG>KEY_MESSAGE</STRONG>     Message key
              <STRONG>KEY_MOUSE</STRONG>       Mouse event occurred
              <STRONG>KEY_MOVE</STRONG>        Move key
              <STRONG>KEY_NEXT</STRONG>        Next object key
              <STRONG>KEY_OPEN</STRONG>        Open key
              <STRONG>KEY_OPTIONS</STRONG>     Options key
              <STRONG>KEY_PREVIOUS</STRONG>    Previous object key
              <STRONG>KEY_REDO</STRONG>        Redo key
              <STRONG>KEY_REFERENCE</STRONG>   Ref(erence) key
              <STRONG>KEY_REFRESH</STRONG>     Refresh key
              <STRONG>KEY_REPLACE</STRONG>     Replace key
              <STRONG>KEY_RESIZE</STRONG>      Screen resized
              <STRONG>KEY_RESTART</STRONG>     Restart key
              <STRONG>KEY_RESUME</STRONG>      Resume key
              <STRONG>KEY_SAVE</STRONG>        Save key
              <STRONG>KEY_SELECT</STRONG>      Select key
              <STRONG>KEY_SUSPEND</STRONG>     Suspend key
              <STRONG>KEY_UNDO</STRONG>        Undo key
              -----------------------------------------------------------------
              <STRONG>KEY_SBEG</STRONG>        Shifted beginning key
              <STRONG>KEY_SCANCEL</STRONG>     Shifted cancel key
              <STRONG>KEY_SCOMMAND</STRONG>    Shifted command key
              <STRONG>KEY_SCOPY</STRONG>       Shifted copy key
              <STRONG>KEY_SCREATE</STRONG>     Shifted create key

              <STRONG>KEY_SDC</STRONG>         Shifted delete character key
              <STRONG>KEY_SDL</STRONG>         Shifted delete line key
              <STRONG>KEY_SEND</STRONG>        Shifted end key
              <STRONG>KEY_SEOL</STRONG>        Shifted clear line key
              <STRONG>KEY_SEXIT</STRONG>       Shifted exit key
              <STRONG>KEY_SFIND</STRONG>       Shifted find key
              <STRONG>KEY_SHELP</STRONG>       Shifted help key
              <STRONG>KEY_SHOME</STRONG>       Shifted home key
              <STRONG>KEY_SIC</STRONG>         Shifted insert key
              <STRONG>KEY_SLEFT</STRONG>       Shifted left arrow key
              <STRONG>KEY_SMESSAGE</STRONG>    Shifted message key
              <STRONG>KEY_SMOVE</STRONG>       Shifted move key
              <STRONG>KEY_SNEXT</STRONG>       Shifted next object key
              <STRONG>KEY_SOPTIONS</STRONG>    Shifted options key
              <STRONG>KEY_SPREVIOUS</STRONG>   Shifted previous object key
              <STRONG>KEY_SPRINT</STRONG>      Shifted print key
              <STRONG>KEY_SREDO</STRONG>       Shifted redo key
              <STRONG>KEY_SREPLACE</STRONG>    Shifted replace key
              <STRONG>KEY_SRIGHT</STRONG>      Shifted right arrow key
              <STRONG>KEY_SRSUME</STRONG>      Shifted resume key
              <STRONG>KEY_SSAVE</STRONG>       Shifted save key
              <STRONG>KEY_SSUSPEND</STRONG>    Shifted suspend key
              <STRONG>KEY_SUNDO</STRONG>       Shifted undo key

       Many keyboards feature a nine-key directional pad.

                                   +-----+------+-------+
                                   | A1  |  up  |  A3   |
                                   +-----+------+-------+
                                   |left |  B2  | right |
                                   +-----+------+-------+
                                   | C1  | down |  C3   |
                                   +-----+------+-------+
       Two of the symbols in the list above do <EM>not</EM> correspond  to  a  physical
       key.

       <STRONG>o</STRONG>   <STRONG>wgetch</STRONG>  returns  <STRONG>KEY_RESIZE</STRONG>,  even  if  the window's keypad mode is
           disabled, if <EM>ncurses</EM> has handled a <STRONG>SIGWINCH</STRONG> signal since <STRONG>wgetch</STRONG> was
           called; see <STRONG><A HREF="curs_initscr.3x.html">initscr(3x)</A></STRONG> and <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>.

       <STRONG>o</STRONG>   <STRONG>wgetch</STRONG>  returns <STRONG>KEY_MOUSE</STRONG> to indicate that a mouse event is pending
           collection; see <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>.  Receipt of this  code  requires  a
           window's  keypad  mode  to  be  enabled, because to interpret mouse
           input (as with <STRONG>xterm(1)</STRONG>'s mouse protocol),  <EM>ncurses</EM>  must  read  an
           escape sequence, as with a function key.


</PRE><H3><a name="h3-Testing-Key-Codes">Testing Key Codes</a></H3><PRE>
       In  <EM>ncurses</EM>,  <STRONG>has_key</STRONG>  returns  a  Boolean value indicating whether the
       terminal type recognizes its parameter as a key code value.   See  also
       <STRONG><A HREF="define_key.3x.html">define_key(3x)</A></STRONG> and <STRONG><A HREF="key_defined.3x.html">key_defined(3x)</A></STRONG>.


</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
       <STRONG>wgetch</STRONG> returns a key code identifying the key event as described above,
       which may include <STRONG>KEY_RESIZE</STRONG> or <STRONG>KEY_MOUSE</STRONG> indicating non-key events, or
       <STRONG>ERR</STRONG> on failure.  <STRONG>wgetch</STRONG> fails if

       <STRONG>o</STRONG>   its timeout expires without any data arriving, or

       <STRONG>o</STRONG>   execution  was  interrupted by a signal, in which case <EM>errno</EM> is set
           to <EM>EINTR</EM>.

       <STRONG>ungetch</STRONG> returns <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on  failure.   <STRONG>ungetch</STRONG>  fails  if
       there is no more room in the input queue.

       <STRONG>has_key</STRONG> returns <STRONG>TRUE</STRONG> or <STRONG>FALSE</STRONG>.

       Functions  taking  a  <EM>WINDOW</EM>  pointer  argument  fail  if <EM>win</EM> is a null
       pointer.

       Functions prefixed with "mv" first perform cursor movement and fail  if
       the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.


</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
       <STRONG>getch</STRONG>, <STRONG>mvgetch</STRONG>, and <STRONG>mvwgetch</STRONG> may be implemented as macros.

       <EM>curses</EM>  discourages assignment of the ESC key to a discrete function by
       the programmer because the library requires a delay while it awaits the
       potential remainder of a terminal escape sequence.

       Some  key  strokes  are  indistinguishable from control characters; for
       example, <STRONG>KEY_ENTER</STRONG> may be the same as <STRONG>^M</STRONG>, and <STRONG>KEY_BACKSPACE</STRONG> may be  the
       same  as <STRONG>^H</STRONG> or <STRONG>^?</STRONG>.  Consult the <EM>terminfo</EM> entry for the terminal type to
       determine whether this  is  the  case;  see  <STRONG><A HREF="infocmp.1m.html">infocmp(1)</A></STRONG>.   Some  <EM>curses</EM>
       implementations, including <EM>ncurses</EM>, honor the <EM>terminfo</EM> key definitions;
       others treat such control characters specially.

       <EM>curses</EM> distinguishes the Enter  keys  in  the  alphabetic  and  numeric
       keypad  sections  of a keyboard because (most) terminals do.  <STRONG>KEY_ENTER</STRONG>
       refers to the key on the numeric keypad and, like other function  keys,
       is reliably recognized only if the window's keypad mode is enabled.

       <STRONG>o</STRONG>   The  <EM>terminfo</EM>  <STRONG>key_enter</STRONG>  (<STRONG>kent</STRONG>) capability describes the character
           (sequence) sent by the  Enter  key  of  a  terminal's  numeric  (or
           similar) keypad.

       <STRONG>o</STRONG>   "Enter or send" is X/Open Curses's description of this key.

       <EM>curses</EM>  treats the Enter or Return key in the <EM>alphabetic</EM> section of the
       keyboard differently.

       <STRONG>o</STRONG>   It usually produces a control code for carriage return (<STRONG>^M</STRONG>) or line
           feed (<STRONG>^J</STRONG>).

       <STRONG>o</STRONG>   Depending  on  the  terminal  mode (raw, cbreak, or canonical), and
           whether <STRONG><A HREF="curs_inopts.3x.html">nl(3x)</A></STRONG> or <STRONG><A HREF="curs_inopts.3x.html">nonl(3x)</A></STRONG>  has  been  called,  <STRONG>wgetch</STRONG>  may  return
           either  a  carriage return or line feed upon an Enter or Return key
           stroke.

       Use of <STRONG>wgetch</STRONG> with <STRONG><A HREF="curs_inopts.3x.html">echo(3x)</A></STRONG> and neither <STRONG><A HREF="curs_inopts.3x.html">cbreak(3x)</A></STRONG> nor <STRONG><A HREF="curs_inopts.3x.html">raw(3x)</A></STRONG>  is  not
       well-defined.

       Historically,  the  list of key code macros above was influenced by the
       keyboard of the AT&amp;T 7300 (also known variously as the  "3B1",  "Safari
       4",  and  "UNIX  PC"),  a  1985 machine rich in function keys.  Today's
       computer keyboards are based on that of the IBM PC/AT and tend to  have
       fewer.  A <EM>curses</EM> application can expect such a keyboard to transmit key
       codes  <STRONG>KEY_UP</STRONG>,  <STRONG>KEY_DOWN</STRONG>,  <STRONG>KEY_LEFT</STRONG>,  <STRONG>KEY_RIGHT</STRONG>,   <STRONG>KEY_HOME</STRONG>,   <STRONG>KEY_END</STRONG>,
       <STRONG>KEY_PPAGE</STRONG>  (Page  Up),  <STRONG>KEY_NPAGE</STRONG>  (Page Down), <STRONG>KEY_IC</STRONG> (Insert), <STRONG>KEY_DC</STRONG>
       (Delete), <STRONG>KEY_A1</STRONG>, <STRONG>KEY_A3</STRONG>, <STRONG>KEY_B2</STRONG>, <STRONG>KEY_C1</STRONG>, <STRONG>KEY_C3</STRONG>, and <STRONG>KEY_F(</STRONG><EM>n</EM><STRONG>)</STRONG> for 1 &lt;=
       <EM>n</EM> &lt;= 12.


</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
       In <EM>ncurses</EM>, when a window's "no time-out" mode is <EM>not</EM> set, the <STRONG>ESCDELAY</STRONG>
       variable configures the duration of the timer used  to  disambiguate  a
       function  key character sequence from a series of key strokes beginning
       with ESC typed by the user; see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.

       <STRONG>has_key</STRONG> is an <EM>ncurses</EM> extension, and  is  not  found  in  SVr4  <EM>curses</EM>,
       4.4BSD <EM>curses</EM>, or any other previous <EM>curses</EM> implementation.


</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
       Applications employing <EM>ncurses</EM> extensions should condition their use on
       the visibility of the <STRONG>NCURSES_VERSION</STRONG> preprocessor macro.

       Except as noted in section "EXTENSIONS" above,  X/Open  Curses  Issue 4
       describes these functions.  It specifies no error conditions for them.

       SVr4  describes  a  successful  return  value only as "an integer value
       other than <EM>ERR</EM>".

       <EM>wgetch</EM> reads only single-byte characters.

       The echo behavior of these functions on  input  of  <EM>KEY</EM><STRONG>_</STRONG>  or  backspace
       characters is not documented in SVr4 <EM>curses</EM>.

       The  behavior  of  <EM>wgetch</EM>  in  the  presence  of signal handlers is not
       documented in SVr4 <EM>curses</EM> and is  unspecified  by  X/Open  Curses.   In
       historical  <EM>curses</EM>  implementations, it varied depending on whether the
       operating system's dispatch of a signal  to  a  handler  interrupted  a
       <STRONG>read(2)</STRONG> call in progress, and also (in some implementations) whether an
       input timeout or non-blocking mode had been  set.   A  portable  <EM>curses</EM>
       application  prepares  for  two  cases:  (a)  signal  receipt  does not
       interrupt <EM>wgetch</EM>; or (b) signal receipt interrupts <EM>wgetch</EM> and causes it
       to return <EM>ERR</EM> with <EM>errno</EM> set to <EM>EINTR</EM>.

       <EM>KEY</EM><STRONG>_</STRONG><EM>MOUSE</EM> is mentioned in X/Open Curses, along with a few related <EM>term-</EM>
       <EM>info</EM> capabilities, but no higher-level functions use the feature.   The
       implementation in <EM>ncurses</EM> is an extension.

       <EM>KEY</EM><STRONG>_</STRONG><EM>RESIZE</EM>  and  <EM>has</EM><STRONG>_</STRONG><EM>key</EM>  are extensions first implemented for <EM>ncurses</EM>.
       By  2022,  <EM>PDCurses</EM>  and  NetBSD  <EM>curses</EM>  had  added  them  along  with
       <EM>KEY</EM><STRONG>_</STRONG><EM>MOUSE</EM>.


</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
       ECMA-6  "7-bit  coded  Character  Set" &lt;https://ecma-international.org/
       publications-and-standards/standards/ecma-6/&gt;

       ECMA-48  "Control  Functions  for  Coded  Character   Sets"   &lt;https://
       ecma-international.org/publications-and-standards/standards/ecma-48/&gt;

       <STRONG><A HREF="curs_get_wch.3x.html">curs_get_wch(3x)</A></STRONG>  describes comparable functions of the <EM>ncurses</EM> library
       in its wide-character configuration (<EM>ncursesw</EM>).

       <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>,    <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>,     <STRONG><A HREF="curs_inopts.3x.html">curs_inopts(3x)</A></STRONG>,     <STRONG><A HREF="curs_mouse.3x.html">curs_mouse(3x)</A></STRONG>,
       <STRONG><A HREF="curs_move.3x.html">curs_move(3x)</A></STRONG>,  <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>,
       <STRONG><A HREF="resizeterm.3x.html">resizeterm(3x)</A></STRONG>, <STRONG>ascii(7)</STRONG>



ncurses 6.5                       2025-02-15                    <STRONG><A HREF="curs_getch.3x.html">curs_getch(3x)</A></STRONG>
</PRE>
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<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
<li><a href="#h3-Reading-Characters">Reading Characters</a></li>
<li><a href="#h3-Keypad-Mode">Keypad Mode</a></li>
<li><a href="#h3-Ungetting-Characters">Ungetting Characters</a></li>
<li><a href="#h3-Predefined-Key-Codes">Predefined Key Codes</a></li>
<li><a href="#h3-Testing-Key-Codes">Testing Key Codes</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
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